The human foot is commonly subjected to strong forces even during ordinary daily activity. Athletes frequently subject their feet to particularly severe shock forces and shearing forces during intense physical activity such as jumping. As a result, a variety of injuries to the foot are sustained by athletes. In addition, chronic conditions may develop as a result of continual stressing of the foot. These conditions produce the overuse syndrome, caused by impact shock, hypermobility, and imbalance. One such condition is known as plantar fascists.
The plantar fascia is a tough fibrous band within the foot that extends from the bottom of the heel bone to each of the toes. The bottom or plantar structures of the foot are supported by bones, muscles, ligaments and inelastic connective tissue called “fascia.”
The plantar fascia serves several important functions. First, it prevents the foot from over-spreading while the foot is supporting the body weight. Second, it provides a springing force during push-off of the foot during motion, for example jumping. It is therefore important that the plantar fascia remain rigid enough to maintain the foot in an unspread position while maintaining sufficient elasticity to provide the desired springing force. Third, the plantar fascia prevents the arch structures from collapsing, and fourth, provides stability of the forefoot on the rearfoot against supporting surfaces during the lift-off phase of gait. Once stabilized against the ground during gait, as the heel lifts and as the toes roll up, the windlass action of the normal plantar fascia, in conjunction with the calf muscle, will lift, pull forward, and invert (resupinate) the heel bone restoring the medial longitudinal arch. Fifth, the plantar fascia acts as a bowstring that maintains flexibility under tension by anchoring the support structures at both ends of the arch. The plantar fascia is the retaining cable of the longitudinal arch. The plantar fascia assists in resupination of the subtalar joint during the propulsive phase of walking gait. The plantar fascia assists the deep posterior muscles by helping to limit subtalar joint pronation during standing and walking. The plantar fascia is under the greatest tension just before the heel lifts off the ground. Sixth, the plantar fascia acts to store energy within the arch structure of the foot during dynamic loading, standing, walking, running. Therefore, the plantar fascia acts like a spring under the arch of the foot to first absorb energy during weight-bearing and restore the relaxed position as the arch rises.
If a sufficient impact, strain or pressure is exerted upon the bottom of the foot, the plantar fascia may over-stretch or develop micro-tears, tears at its attachment from tension pulling on the heel bone as the foot moves upwards at the ankle joint. This condition is known as plantar fasciistis. Plantar fasciistis seldom develops as the result of a single traumatic occurrence or injury, but rather develops slowly as the result of activities which place recurring stress upon the plantar fascia. For example, wearing shoes which lack adequate arch support for the foot or shank support within the shoe can provide such stress, particularly for individuals with the extremes of hypermobile flat feet or rigid high arched feet. Also, shoes with very stiff soles may require exertion of additional force to flex under the ball of the foot. In addition, increased stress on the plantar fascia due to increased weight or high-impact sports may result in plantar fasciistis.
Plantar fasciitis leads to pain on weight-bearing and tenderness to deep pressure over the plantar fascia at the heel-bone junction. Swelling and inflammation may develop. These conditions worsen with activity. Any activity which causes the foot to spread, such as prolonged standing, or which causes springing of the foot such as running and jumping will aggravate the condition.
Plantar fasciitis is also commonly known as the “heel spur syndrome.” This name arose because as the plantar fascia is under prolonged or increased tension, it becomes excessively stretched for prolonged periods and the point of attachment of the plantar fascia to the heel may become calcified leading to bone growth that is often times referred to as a heel spur. In severe cases of plantar fasciitis, surgery is performed to permanently separate the plantar fascia from the heel spur. This surgery requires months for recovery. The separation of the plantar fascia from the heel results in a collapsed arch, as the plantar fascia is no longer capable of providing support. Surgery therefore results in the need for the permanent use of custom orthotics-arch supports for the foot to be worn within shoes to provide support for the foot. Finally, the plantar fascia is also unable to assist in springing, resulting in diminished locomotion and inability to push off the planted foot.
Early treatment is therefore essential in maintaining long-term active use of the foot. Treatment is focused upon reduction of stress to the foot which would cause the foot to spread. This commonly involves resting the foot or the use of custom orthotics devices. Unfortunately, these orthotics cannot fully support the arch of the foot except while the foot is flat against the ground or other hard surface, as there is no attachment of the orthotic to the foot. The orthotic cannot provide full support to the arch during the critical periods of motion during which the foot is landing or springing forward. Custom made foot arch supports, commercial arch supports, and functional foot orthotic devices support the arch and cup the heel but do not prevent elongation of the foot upon contact or push-off during gait.
Many devices which provide some measure of support to structures of the foot are ineffective in providing support for the plantar fascia. One such device is taught by Alenares, U.S. Pat. No. 4,085,745. Alenares teaches a foot support constructed from a two-way stretch material which provides uniform pressure across the surface of the foot to support the venous system of the foot. Such a support is too elastic in the direction parallel to the length of the foot, hereinafter referred to as the long axis of the foot, to maintain the arch of the foot in a rigid configuration necessary to support the plantar fascia. Ordinary two-way stretch material will not provide such support as long as the material retains equal elasticity in all directions, as rigidity is desired in the direction of the long axis, while some flexibility is desired in the direction perpendicular to the long axis in order to facilitate motion of the foot.
One method successfully used to treat plantar fasciitis is to tape the foot into a resting position in a manner to provide support to the foot. One such method is known as the Low-Dye strap method of taping. In a variation of this method adhesive tape is applied from the arch on the outside of the foot around and under the heel of the foot, wrapping forward and extending to the inner arch of the foot to a point forward of the midfoot. Finally, strips are wrapped about the foot from the instep to the bottom of the foot, encircling the front portion of the foot midshaft of the first metatarsal bone, between the first metatarsal-first cuneiform joint and the first phalangeal-metatarsal joint, which is the joint of the big toe to the foot.
This method provides several advantages. The arch is supported by anchoring points at both ends of the arch, thereby providing mechanical support. This prevents the arch from collapsing and from the foot elongating. The foot is held in a semi-rigid manner, thereby both preventing over-spreading of the foot as well as allowing springing during toe-off by holding the bones and joints of the foot in proper alignment.
Unfortunately, this method has several significant disadvantages. The method requires that the tape be applied on a regular basis. This results in the wearer being required to perform the time consuming task of applying the tape. Many individuals may feel uncomfortable with applying the taping themselves. Thus the difficulty of the procedure discourages use of the method by many individuals who would benefit from its effects.
In addition, the tapes lose their effectiveness if adhesion to the skin is diminished. As a result, taping is ineffective if the foot becomes wet. If the tape becomes wet or disattaches, retaping becomes necessary. The need for retaping may arise under circumstances which are not conducive to the lengthy retaping process, as the wearer will commonly be engaged in some sort of physical activity at the time.
Also, many individuals suffer allergic reactions to the adhesive in the tape. Long term continuous use of adhesive tape on the body may be harmful to the skin. The difficulty in applying the tape may lead to individuals choosing to wear the tape for long periods rather than retaping.
Therefore, there is clearly a strong need for a support apparatus for the foot which provides support to the plantar fascia and the arch of the foot without requiring difficult and time consuming taping procedures or expensive custom made foot orthoses.
Generally, it is an object of the present invention to provide an improved method and support apparatus for the plantar fascia of the foot.
Another object of the present invention is to provide a support apparatus for the plantar fascia of the foot which may be easily placed in operative position on the foot and designed to be used interchangeably on the right or left foot, or inside—out. Other objects of the present invention will become apparent to those skilled in the art from the following description and accompanying claims and drawings.